Design and construction of non-rectangular batteries

ABSTRACT

The disclosed embodiments relate to a battery cell which includes a first electrode sheet having a first area and a second electrode sheet having a second area. The second area may be less than the first area. The battery cell also includes a first conductive tab coupled to the first electrode sheet and a second conductive tab coupled to the second electrode sheet. An insulator is disposed between the second conductive tab and the first electrode sheet, the insulator configured to prevent electrical current from flowing between the first electrode sheet and the second conductive tab. The battery cell also includes a pouch that encloses the first and second electrode sheets and a first and second battery terminal extending through the pouch. The first battery terminal may be coupled to the first conductive tab, and the second battery terminal may be coupled to the second conductive tab.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/606,975, entitled “Design and Construction of Non-RectangularBatteries,” filed on Jan. 27, 2015, now U.S. Pat. No. 10,135,097, whichis a continuation of U.S. patent application Ser. No. 12/837,932,entitled “Design and Construction of Non-Rectangular Batteries,” filedon Jul. 16, 2010, now U.S. Pat. No. 8,940,429, each of which isincorporated by reference in its entirety as if fully disclosed herein.

TECHNICAL FIELD

The present embodiments relate to batteries for portable electronicdevices. More specifically, the present embodiments relate to the designand constructions of non-rectangular battery cells to facilitateefficient use of space within portable electronic devices.

BACKGROUND

Rechargeable batteries are presently used to provide power to a widevariety of portable electronic devices, including laptop computers,mobile phones, PDAs, digital music players and cordless power tools. Themost commonly used type of rechargeable battery is a lithium battery,which can include a lithium-ion or a lithium-polymer battery.

Lithium-polymer batteries often include cells that are packaged inflexible pouches. Such pouches are typically lightweight and inexpensiveto manufacture. Moreover, pouches may be tailored to various celldimensions, allowing lithium-polymer batteries to be used inspace-constrained portable electronic devices such as mobile phones,laptop computers, and/or digital cameras. For example, a lithium-polymerbattery cell may achieve a packaging efficiency of 90-95% by enclosingrolled electrodes and electrolyte in an aluminized laminated pouch.Multiple pouches may then be placed side-by-side within a portableelectronic device and electrically coupled in series and/or in parallelto form a battery for the portable electronic device.

However, efficient use of space may be limited by the use andarrangement of cells in existing battery pack architectures. Inparticular, battery packs typically contain rectangular cells of thesame capacity, size, and dimensions. The physical arrangement of thecells may additionally mirror the electrical configuration of the cells.For example, a six-cell battery pack may include six lithium-polymercells of the same size and capacity configured in a two in series, threein parallel (2s3p) configuration. Within the battery pack, two rows ofthree cells placed side-by-side may be stacked on top of each other;each row may be electrically coupled in a parallel configuration and thetwo rows electrically coupled in a series configuration. Consequently,the battery pack may require space in a portable electronic device thatis at least the length of each cell, twice the thickness of each cell,and three times the width of each cell. Furthermore, the battery packmay be unable to utilize free space in the portable electronic devicethat is outside of a rectangular space reserved for the battery pack.

Hence, the use of portable electronic devices may be facilitated byimprovements related to the packaging efficiency, capacity, form factor,cost, design, and/or manufacturing of battery packs containinglithium-polymer battery cells.

SUMMARY

The disclosed embodiments relate to a battery cell which includes afirst electrode sheet having a first area and a second electrode sheethaving a second area. The second area may be less than the first area.The battery cell also includes a first conductive tab coupled to thefirst electrode sheet and a second conductive tab coupled to the secondelectrode sheet. The battery cell further includes an insulator disposedbetween the second conductive tab and the first electrode sheet, theinsulator configured to prevent electrical current from flowing betweenthe first electrode sheet and the second conductive tab. The batterycell also includes a pouch that encloses the first and second electrodesheets and a first and second battery terminal extending through thepouch. The first battery terminal may be coupled to the first conductivetab, and the second battery terminal may be coupled to the secondconductive tab.

A method for providing a power source for a portable electronic deviceis disclosed. The method includes arranging a first electrode sheet anda second electrode sheet in a stacked configuration, the first electrodesheet having a first area and the second electrode sheet having a secondarea that is less than the first area. The method further includesconnecting a first conductive tab to a first battery terminal, the firstconductive tab extending from the first electrode sheet, and connectinga second conductive tab to a second battery terminal, the secondconductive tab extending from the second electrode sheet. The methodalso includes disposing an insulator in between the second conductivetab and the first electrode sheet, the insulator configured to preventelectrical current from flowing between the first electrode sheet to thesecond conductive tab, and enclosing the first and second electrodesheets in a pouch.

In some embodiments, a portable electronic device is disclosed thatincludes a set of components powered by a battery pack. The battery packincludes a first electrode sheet having a first area, a second electrodesheet having a second area that is less than the first area, a firstconductive tab coupled to the first electrode sheet, and a secondconductive tab coupled to the second electrode sheet. An insulator isdisposed between the second conductive tab and the first electrode sheetand is configured to prevent electrical current from flowing between thefirst electrode sheet and the second conductive tab. The battery packalso includes a pouch to enclose the first and second electrode sheets,and a first and second battery terminal extending through the pouch. Thefirst battery terminal may be coupled to the first conductive tab, andthe second battery terminal may be coupled to the second conductive tab.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a battery cell in accordance with an embodiment.

FIG. 2 shows a non-rectangular design for a battery cell in accordancewith an embodiment.

FIG. 3 shows a non-rectangular design for a battery cell in accordancewith an embodiment.

FIG. 4 shows a non-rectangular design for a battery cell in accordancewith an embodiment.

FIG. 5 shows a non-rectangular design for a battery cell in accordancewith an embodiment.

FIG. 6 shows the placement of a battery within a portable electronicdevice in accordance with an embodiment.

FIG. 7 shows the placement of a battery within a portable electronicdevice in accordance with an embodiment.

FIG. 8 shows a flowchart illustrating the process of manufacturing abattery cell in accordance with an embodiment.

FIG. 9 shows a portable electronic device in accordance with anembodiment.

In the figures, like reference numerals refer to the same figureelements.

DETAILED DESCRIPTION

The following description is presented to enable any person skilled inthe art to make and use the embodiments, and is provided in the contextof a particular application and its requirements. Various modificationsto the disclosed embodiments will be readily apparent to those skilledin the art, and the general principles defined herein may be applied toother embodiments and applications without departing from the spirit andscope of the present disclosure. Thus, the present invention is notlimited to the embodiments shown, but is to be accorded the widest scopeconsistent with the principles and features disclosed herein.

The data structures and code described in this detailed description aretypically stored on a computer-readable storage medium, which may be anydevice or medium that can store code and/or data for use by a computersystem. The computer-readable storage medium includes, but is notlimited to, volatile memory, non-volatile memory, magnetic and opticalstorage devices such as disk drives, magnetic tape, CDs (compact discs),DVDs (digital versatile discs or digital video discs), or other mediacapable of storing code and/or data now known or later developed.

The methods and processes described in the detailed description sectioncan be embodied as code and/or data, which can be stored in acomputer-readable storage medium as described above. When a computersystem reads and executes the code and/or data stored on thecomputer-readable storage medium, the computer system performs themethods and processes embodied as data structures and code and storedwithin the computer-readable storage medium.

Furthermore, methods and processes described herein can be included inhardware modules or apparatus. These modules or apparatus may include,but are not limited to, an application-specific integrated circuit(ASIC) chip, a field-programmable gate array (FPGA), a dedicated orshared processor that executes a particular software module or a pieceof code at a particular time, and/or other programmable-logic devicesnow known or later developed. When the hardware modules or apparatus areactivated, they perform the methods and processes included within them.

The disclosed embodiments provide a battery cell with a non-rectangulardesign. The battery cell may include a set of electrode sheets ofdifferent dimensions arranged in a stacked configuration. Thenon-rectangular shape of the stacked configuration may facilitateefficient use of space in a portable electronic device. The term“non-rectangular” can mean that the cells are not rectangular throughany cutting plane, which means that the cells are not rectangular whenviewed from the top, bottom, or sides. For example, the non-rectangularstacked configuration may be based on a toroidal design, an L-shapeddesign, a triangular design, a pie-shaped design, a cone-shaped design,and/or a pyramidal design. The electrode sheets may also be enclosed ina pouch to form a lithium-polymer battery cell. Moreover, a rigid platemay be disposed beneath the electrode sheets inside the pouch to providestructural support for the battery cell.

The electrode sheets may then be electrically coupled in a parallelconfiguration. In particular, the cathode of each electrode sheet may beelectrically coupled to one of a first set of conductive tabs, and theanode of each electrode sheet may be electrically coupled to one of asecond set of conductive tabs. The first set of conductive tabs may thenbe electrically coupled using a wire-bonding technique, a spot-weldingtechnique, a crimping technique, a riveting technique, and/or anultrasonic-welding technique. The same technique(s) may also be used toelectrically couple the second set of conductive tabs. The first andsecond sets of conductive tabs may extend through seals in the pouch toprovide terminals for the battery cell.

FIG. 1 shows a battery cell in accordance with an embodiment. Thebattery cell may supply power to a portable electronic device such as alaptop computer, mobile phone, tablet computer, personal digitalassistant (PDA), portable media player, digital camera, and/or othertype of battery-powered electronic device.

As shown in FIG. 1, the battery cell includes a number of layers 102,104, 106 and 108 that form a wedge-shaped, terraced structure. Layers102-108 may be formed from thin electrode sheets; each electrode sheetmay provide a cathode for the battery cell on one side and an anode forthe battery cell on the other side. For example, each electrode sheetmay have a thickness of around 20 microns. The electrode sheet may alsoinclude an anode of lithium or zinc and a cathode of manganese dioxide.

Moreover, the electrode sheets may be arranged in a stackedconfiguration to form layers 102-108. In particular, the terraced,curved structure of the battery cell may be created using flatpie-shaped electrode sheets of four different sizes. First, a series ofelectrode sheets of the largest size may be stacked to form layer 102,then a series of smaller pie-shaped electrode sheets may be stacked ontop of layer 102 to form layer 104. After layers 102-104 are formed, anumber of the third-largest electrode sheets may be stacked on top oflayer 104 to form layer 106, and finally, the smallest electrode sheetsare placed on top of layer 106 to form layer 108.

To form a power source, the electrode sheets may be electrically coupledin a parallel configuration and enclosed in a pouch 116. To electricallycouple the electrode sheets, each cathode from the electrode sheets maybe electrically coupled to one of a first set of conductive tabs, andeach anode from the electrode sheets may be electrically coupled to oneof a second set of conductive tabs. The first set of conductive tabs maythen be electrically coupled using a wire-bonding technique, aspot-welding technique, a crimping technique, a riveting technique,and/or an ultrasonic-welding technique to form a positive terminal 110for the battery cell.

The same technique(s) may also be used to electrically couple the secondset of conductive tabs to form a negative terminal 112 for the batterycell. For example, the battery cell may be assembled by stackingelectrode sheets coupled to conductive tabs against one or more surfacesthat align the corners of the electrode sheets and the conductive tabs.The conductive tabs may then be spot-welded together to form terminals110-112.

To enclose the battery cell in pouch 116, layers 102-108 may be placedon top of a sheet of polymer laminate and/or another type of flexiblepouch material. Another sheet of pouch material may then be placed overthe tops of layers 102-108, and the two sheets may be heat-sealed and/orfolded. Alternatively, layers 102-108 may be placed in between twosheets of pouch material that are sealed and/or folded on some (e.g.,non-terminal) sides. The remaining side(s) may then be heat-sealedand/or folded to enclose layers 102-108 within pouch 116. Terminals110-112 may extend through seals in pouch 116 to allow the battery cellto be electrically coupled to other components in the portableelectronic device.

Those skilled in the art will appreciate that the thin and/or flexiblenature of the electrode sheets may cause the electrode sheets to bendand/or deform within the battery cell during handling and/orinstallation within the portable electronic device. As a result, a rigidplate 114 may be disposed beneath layers 102-108 to provide structuralsupport for the battery cell.

In one or more embodiments, the battery cell of FIG. 1 facilitatesefficient use of space within the portable electronic device. Forexample, the terraced and/or curved edges of the battery cell may allowthe battery cell to fit within a curved enclosure for the portableelectronic device. The number of layers (e.g., layers 102-108) may alsobe increased or decreased to better fit the curvature of the portableelectronic device's enclosure. In other words, the battery cell mayinclude an asymmetric and/or non-rectangular design that accommodatesthe shape of the portable electronic device. In turn, the battery cellmay provide greater capacity, packaging efficiency, and/or voltage thanrectangular battery cells in the same portable electronic device.Non-rectangular designs for battery cells are discussed in furtherdetail below with respect to FIGS. 2-5.

FIG. 2 shows a non-rectangular design for a battery cell in accordancewith an embodiment. More specifically, FIG. 2 shows a top-down view of abattery cell with a number of layers 202, 204, 206 and 208. Layers202-208 may be formed by arranging electrode sheets of differentdimensions in a stacked configuration that is based on a toroidal and/orcone-shaped design for the battery cell. Consequently, the electrodesheets used in the battery cell of FIG. 2 may be round and/orellipsoidal.

Moreover, the electrode sheets forming layers 202-208 may be hollow toenable the formation of two terminals 210-212. Each terminal 210-212 mayinclude a set of conductive tabs that connects the cathodes or theanodes of the electrode sheets. For example, terminal 210 may correspondto a positive terminal for the battery cell and include a first set ofconductive tabs electrically coupled to one another and to the cathodesof the electrode sheets. Terminal 212 may correspond to a negativeterminal for the battery cell and include a second set of conductivetabs electrically coupled to one another and to the anodes of theelectrode sheets.

The battery cell of FIG. 2 may be designed to fit around the perimeterof a portable electronic device. For example, layers 202-208 mayaccommodate a curved and/or scalloped outline of the portable electronicdevice, while the hollow interior of the battery cell may allowcomponents (e.g., printed circuit boards (PCBs), processors, memory,storage, display, optical drives, etc.) to be placed in the middle ofthe portable electronic device. Placement of battery cells withinportable electronic devices is discussed in further detail below withrespect to FIGS. 6-7.

FIG. 3 shows a non-rectangular design for a battery cell in accordancewith an embodiment. As with the battery cell of FIG. 2, the battery cellof FIG. 3 includes a number of layers 302, 304, 306, 308 and 310 formedby stacking round and/or ellipsoidal electrode sheets of the samethickness (e.g., 10-20 microns) and varying sizes. However, becauselayers 302-310 are not hollow, terminals 312-314 for the battery cellmay be placed outside layers 302-310. The skewed-cone shape of thebattery cell may allow the battery cell to fit within a recessed pocketin a portable electronic device.

FIG. 4 shows a non-rectangular design for a battery cell in accordancewith an embodiment. The battery cell of FIG. 4 may be formed from fourlayers 402, 404, 406 and 408 of triangular electrode sheets that arealigned along one edge and stacked. Each layer individual layer 402,404, 406 and 408 may include electrode sheets of the same size, whilethe different layers 402, 404, 406 and 408 may be formed from electrodesheets of four different sizes. The battery cell may thus be based on apyramidal and/or triangular design. Furthermore, a set of terminals410-412 may electrically couple the electrode sheets in a parallelconfiguration and allow the battery cell to supply power to a portableelectronic device.

FIG. 5 shows a non-rectangular design for a battery cell in accordancewith an embodiment. The battery cell of FIG. 5 may include four layers502, 504, 506 and 508 of square electrode sheets arranged in a stackedconfiguration. However, unlike the battery cells of FIGS. 1-4, theelectrode sheets of FIG. 5 may be centered on top of each other. As aresult, terminals 510-512 for the battery cell may be formed fromconductive tabs that overlap with surfaces of electrode sheets to whichthe conductive tabs should not be electrically coupled. For example,conductive tabs that are electrically coupled to electrode sheets oflayer 504 may overlap with the topmost electrode sheet of layer 502.

To prevent electric current from flowing between overlapping electrodesheets and conductive tabs, a conductive tab may be insulated from anoverlapping surface of an electrode sheet to which the conductive tabshould not be electrically coupled by placing a layer of insulatingmaterial such as Kapton (Kapton™ is a registered trademark of E. I. duPont de Nemours and Company Corporation) in between the conductive taband the electrode sheet. Such use of insulating materials in the batterycell may enable the creation of battery cells of arbitrarythree-dimensional (3D) shapes, which in turn may further facilitate theefficient use of space inside portable electronic devices that use thebattery cells.

FIG. 6 shows the placement of a battery 602 within a portable electronicdevice in accordance with an embodiment. As shown in FIG. 6, a top-downview of battery 602 shows that battery 602 is placed along the outsideperimeter of the portable electronic device. Furthermore, the batterymay include a toroidal, L-shaped, and/or pie-shaped design toaccommodate a curved and/or scalloped shape of the portable electronicdevice. The interior of the battery may be hollow to allow components tobe placed within the portable electronic device.

FIG. 7 shows the placement of a battery 702 within a portable electronicdevice in accordance with an embodiment. Battery 702 may be based on thesame design as battery 602 of FIG. 6. More specifically, across-sectional view of battery 702 shows that battery 702 fills up thespace along the curved sides of the portable electronic device. As aresult, battery 702 may represent increased packaging efficiency and/orcapacity over a rectangular battery that is used in the same portableelectronic device.

FIG. 8 shows a flowchart illustrating the process of manufacturing abattery cell in accordance with an embodiment. In one or moreembodiments, one or more of the steps may be omitted, repeated, and/orperformed in a different order. Accordingly, the specific arrangement ofsteps shown in FIG. 8 should not be construed as limiting the scope ofthe embodiments.

First, a set of electrode sheets of different dimensions is arranged ina stacked configuration to facilitate efficient use of space within aportable electronic device (operation 802). For example, electrodesheets of the same thickness and varying lengths and/or widths may bestacked to form a battery cell that is based on a non-rectangular (e.g.,toroidal, L-shaped, triangular, pie-shaped, cone-shaped, pyramidal)battery design.

Next, the electrode sheets are electrically coupled in a parallelconfiguration (operation 804). Each cathode from the electrode sheetsmay be electrically coupled to one of a first set of conductive tabs,and each anode from the electrode sheets may be electrically coupled toone of a second set of conductive tabs. The first set of conductive tabsmay then be electrically coupled using a wire-bonding technique, aspot-welding technique, a crimping technique, a riveting technique,and/or an ultrasonic-welding technique to form a positive terminal forthe battery cell. The same technique(s) may also be used to electricallycouple the second set of conductive tabs to form a negative terminal forthe battery cell. In addition, a conductive tab may be insulated from anoverlapping surface of an electrode sheet to which the conductive tabshould not be electrically coupled by placing a layer of insulatingmaterial such as Kapton in between the conductive tab and the electrodesheet.

A rigid plate may also be disposed beneath the electrode sheets(operation 806) to provide structural support for the battery cell. Suchstructural support may prevent the battery cell from flexing and/ordistorting during handling and/or installation within a portableelectronic device. Finally, the electrode sheets and rigid plate may beenclosed in a pouch (operation 808). Consequently, the battery cell maycorrespond to a lithium-polymer battery cell that is designed toaccommodate the shape of the portable electronic device. For example,the battery cell may be placed within a curved interior of the portableelectronic device to provide increased capacity and/or packagingefficiency over battery packs containing rectangular cells.

The above-described rechargeable battery cell can generally be used inany type of electronic device. For example, FIG. 9 illustrates aportable electronic device 900 which includes a processor 902, a memory904 and a display 908, which are all powered by a battery 906. Portableelectronic device 900 may correspond to a laptop computer, mobile phone,PDA, portable media player, digital camera, and/or other type ofbattery-powered electronic device. Battery 906 may correspond to abattery pack that includes one or more battery cells. Each battery cellmay include a set of electrode sheets of different dimensions arrangedin a stacked configuration. The stacked configuration may facilitateefficient use of space inside portable electronic device 900. Forexample, the stacked configuration may allow battery 906 to fit alongthe perimeter of a mobile phone with a scalloped shape.

The foregoing descriptions of various embodiments have been presentedonly for purposes of illustration and description. They are not intendedto be exhaustive or to limit the present invention to the formsdisclosed. Accordingly, many modifications and variations will beapparent to practitioners skilled in the art. Additionally, the abovedisclosure is not intended to limit the present invention.

What is claimed is:
 1. A battery cell, comprising: a first electrodesheet having a first area; a second electrode sheet having a secondarea, wherein the second area is less than the first area; a firstconductive tab coupled to the first electrode sheet; a second conductivetab coupled to the second electrode sheet; an insulator disposed betweenthe second conductive tab and the first electrode sheet, the insulatorconfigured to prevent electrical current from flowing between the firstelectrode sheet and the second conductive tab; a pouch enclosing thefirst and second electrode sheets; and a first and second batteryterminal extending through the pouch, wherein the first battery terminalis coupled to the first conductive tab, and wherein the second batteryterminal is coupled to the second conductive tab.
 2. The battery cell ofclaim 1, wherein the first and second electrode sheets are round.
 3. Thebattery cell of claim 1, wherein the first and second electrode sheetsare ellipsoidal.
 4. The battery cell of claim 1, wherein the first andsecond electrode sheets are triangular.
 5. The battery cell of claim 1,wherein the first and second electrode sheets are square.
 6. The batterycell of claim 1, wherein the first and second electrode sheets cooperateto define a terrace at an outer edge of the first and second electrodesheets.
 7. The battery cell of claim 1, wherein at least one of thefirst and second electrode sheets comprises a hollow interior portion.8. The battery cell of claim 1, further comprising a rigid platedisposed proximate to the first electrode sheet, wherein the rigid plateis enclosed by the pouch.
 9. A method for providing a power source for aportable electronic device, comprising: arranging a first electrodesheet and a second electrode sheet in a stacked configuration, whereinthe first electrode sheet has a first area and the second electrodesheet has a second area, wherein the second area is less than the firstarea; connecting a first conductive tab to a first battery terminal,wherein the first conductive tab extends from the first electrode sheet;connecting a second conductive tab to a second battery terminal, whereinthe second conductive tab extends from the second electrode sheet;disposing an insulator in between the second conductive tab and thefirst electrode sheet, the insulator configured to prevent electricalcurrent from flowing between the first electrode sheet to the secondconductive tab; and enclosing the first and second electrode sheets in apouch.
 10. The method of claim 9, wherein the first and second electrodesheets are round.
 11. The method of claim 9, wherein the first andsecond electrode sheets are ellipsoidal.
 12. The method of claim 9,wherein the first and second electrode sheets are triangular.
 13. Themethod of claim 9, wherein the first and second electrode sheets aresquare.
 14. The method of claim 9, wherein the first and secondelectrode sheets cooperate to define a terrace at an outer edge of thefirst and second electrode sheets.
 15. The method of claim 9, wherein atleast one of the first and second electrode sheets comprises a hollowinterior portion.
 16. The method of claim 9, further comprising:disposing a rigid plate proximate to the first electrode sheet; andenclosing the rigid plate within the pouch.
 17. A portable electronicdevice, comprising: a set of components powered by a battery pack, thebattery pack comprising: a first electrode sheet having a first area; asecond electrode sheet having a second area, wherein the second area isless than the first area; a first conductive tab coupled to the firstelectrode sheet; a second conductive tab coupled to the second electrodesheet; an insulator disposed between the second conductive tab and thefirst electrode sheet, the insulator configured to prevent electricalcurrent from flowing between the first electrode sheet and the secondconductive tab; a pouch enclosing the first and second electrode sheets;and a first and second battery terminal extending through the pouch,wherein the first battery terminal is coupled to the first conductivetab, and wherein the second battery terminal is coupled to the secondconductive tab.
 18. The portable electronic device of claim 17, whereinthe first and second electrode sheets cooperate to define a terrace atan outer edge of the first and second electrode sheets.
 19. The portableelectronic device of claim 17, wherein at least one of the first andsecond electrode sheets comprises a hollow interior portion.
 20. Theportable electronic device of claim 17, further comprising a rigid platedisposed proximate to the first electrode sheet, wherein the rigid plateis enclosed by the pouch.